This invention relates to means for checking the battery or batteries in a battery operated device for low voltage.
Many battery powered devices are presently being marketed which have a critical function, making it desirable that a convenient and uncomplicated way be provided to check the viability of the battery power to avoid the need for replacement of batteries for such devices on a regular time basis. for example, it is important that the user of battery powered smoke detectors know if the battery for such a device needs replacing. The 3M Brand heat scanner (model 201 series) is also a battery operated device which is hand held and can be used in critical situations, making it desirable that the user know if its battery sources need replacing.
A number of micropower linear integrated circuits have evolved which can provide the function of sensing for low battery voltage. This approach requires the addition of circuitry to the battery operated device adding to its weight, cost, power consumption and the possible need for one or more separate reference battery power sources and additional space.